1. Field of the Invention
The present invention relates to an electronic torsional tool, and more particularly to an electronic torsional tool provided with a hole and an extending rod to enhance flexibility and deformation of the electronic torsional tool.
2. Description of the Related Art
A conventional pointer type torsional wrench in accordance with the prior art shown in FIG. 8 comprises a drive shank 10 having a first end formed with a drive head 11, a handle 14 pivotally mounted on a second end of the drive shank 10 by a pivot shaft 15, a torsion scale 13 secured on the drive shank 10 and located adjacent to the handle 14, and a pointer rod 12 integrally extended from the drive head 11 and having a free end pointed to the torsion scale 13. The pointer rod 12 is in parallel with the drive shank 10 at the normal state.
In operation, the drive head 11 is fitted on a workpiece (by a socket for example). The operator exerts a force on the handle 14 to rotate the drive shank 10 of the wrench and to operate the workpiece. The handle 14 is pivoted with the drive shank 10 by the pivot shaft 15, so that the force in each direction exerted by the operator on the handle 14 can be concentrated on the pivot shaft 15 and can be transmitted to the drive shank 10 of the wrench. Thus, when the force applied on the drive shank 10 of the wrench exceeds a predetermined value, the pointer rod 12 deviates from the drive shank 10 through a relative angle, so that the pointer 120 of the pointer rod 12 can indicate the torsion value exerted on the wrench by the deflecting angle between the pointer rod 12 and the drive shank 10.
However, the conventional pointer type torsional wrench has the following disadvantages.
1. The operator has to exert a torsional force on the handle 14 successively so that the pointer 120 of the pointer rod 12 can read the torsion values. Thus, the indicated torsion reading values are not accurate because the successive force applied by the operator is not evenly distributed.
2. The pointer rod 12 protrudes from the drive shank 10, so that it is easily hit by a foreign object, thereby affecting the accuracy of the pointer rod 12.
3. The operator has to exert a torsional force on the handle 14 successively so that the pointer 120 of the pointer rod 12 can read the torsion values, thereby wasting the operator's energy.
A conventional spring type torsional wrench 16 in accordance with the prior art shown in FIG. 9 is disclosed in the Taiwanese Patent Publication No. 288375. The output torsion of the torsional wrench 16 is adjustable. When the force applied on the wrench exceeds a predetermined value, the wrench idles, thereby limiting the torsion exerted by the operator to a determined value. However, the torsional wrench 16 cannot clearly indicate the torsion reading values.
A conventional single-rod type torsional wrench 30 in accordance with the prior art shown in FIG. 10 is disclosed in the Taiwanese Patent Publication No. 485872. Another conventional single-rod type torsional wrench 32 in accordance with the prior art shown in FIGS. 11, 12 and 12A is disclosed in the Taiwanese Patent Publication No. 488991. The above-mentioned single-rod type torsional wrench is formed with a plurality of recesses for receiving the strain gauge, the bridge and the digital indicator.
A conventional double-rod type torsional wrench in accordance with the prior art shown in FIG. 13 is disclosed in the U.S. Pat. No. 4,958,541. The above-mentioned double-rod type torsional wrench comprises a solid inner rod 18 co-operating with a strain gauge, and a hollow outer rod 17 mounted on the solid inner rod 18.